A severe limitation in the study of the immunological aspects of host-parasite relationships is a lack of characterized parasite antigens and the identification of those relevant in protection from disease. This project aims to provide information on the immunological events of cutaneous leishmaniasis with a view to developing new tools for control of disease and for identification of antigens relevant in immunodiagnosis. We will use the L.tropica mouse model system to examine parasite antigens playing a role in protective immune responses. Antigens of interest are expressed on infected macrophages and we will analyse their relationship to host histocompatibility antigens, particularly those required as associative recognition molecules by T cells. Monoclonal antibodies will be used to identify antigens common to all Leishmania spp. as well as isolate and strain specific antigens. These antigens will be assessed as vaccine molecules and immunodiagnostic reagents. We will concurrently derive bacterial cDNA clones for genes of relevant L.tropica antigens. Stage-specific cDNA clones will be identified and used to study genomic organization of genes expressed selectively in different life cycle stages. Relevant cDNAs will be sequenced and optimal expression in recombinant hosts will be engineered.